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at time of writing, Masters Candidate, Divisions of Pharmacy Practice and Administration, College of Pharmacy, The University of Texas at Austin, Austin, TX; now, Clinical Pharmacy Specialist/Assistant Professor, Department of Pharmaceutical Care, University of Iowa Hospitals and Clinics, College of Pharmacy, University of Iowa, Iowa City, IA
Clinical Assistant Professor, The University of Texas Medical Branch, Galveston, TX
Pharmacy Site Manager, Seton Shoal Creek Hospital, Austin, TX
Reprints: Dr. Bettinger, Seton Shoal Creek Hospital, 3501 Mills Ave., Austin, TX 78731, fax 512/324-2125, tlbettinger{at}seton.org
OBJECTIVE: To describe the case of a patient with postherpetic neuralgia (PHN) who had a marked response to topiramate despite failure of several previous therapies.
CASE SUMMARY: A 79-year-old white male with multiple medical comorbidities developed severe trigeminal territory PHN requiring treatment with opiates to maintain adequate pain relief. Topiramate was initiated after the patient failed treatment with 4 other antiepileptic medications due to various adverse events. After 3 months of topiramate therapy, with dosages up to 50 mg twice daily, PHN pain had decreased to the point that the patient was able to discontinue the use of opiates entirely. At time of writing, he continued to be maintained on topiramate 50 mg twice daily with good pain relief and no reported adverse effects.
DISCUSSION: Topiramate exhibits a number of actions that may
contribute to the relief of neuropathic pain, including modulation of
voltage-gated sodium and calcium channels, potentiation of
-aminobutyric acid inhibition, and blockade of
-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainite
glutamate receptors. Current evidence-based recommendations consider
topiramate to be a third-line agent for the treatment of neuropathic pain
based on studies of its use in painful diabetic neuropathy and chronic lumbar
radicular pain. A comprehensive search of MEDLINE (1950–August 2008)
using the terms postherpetic neuralgia, neuralgia, and topiramate revealed
only one previously published case report evaluating the use of topiramate
specifically for treatment of PHN.
CONCLUSIONS: While it is impossible to determine whether pain relief in this case was due to treatment with topiramate as opposed to spontaneous resolution of pain over time, this additional case report suggests that topiramate may be a useful treatment option for patients with PHN who have not responded to or are intolerant of other interventions. Further studies are needed to determine whether topiramate should receive a stronger recommendation for the treatment of PHN.
Key Words: anticonvulsants, neuropathic pain, postherpetic neuralgia, topiramate
Published Online, December 23, 2008. www.theannals.com, DOI 10.1345/aph.1L470